Yep. After the 1994 quake knocked down part of I-10 between LA and Santa Monica, the EIR process was waived and a famous contractor hired (was it the original CC Myer firm?) - rebuilt in a few months what normally would take 5-10 years to do. Railroads usually are even faster because they're private - no permits required to rebuild, period. Main thing holding them up in the LA area would be the fallen-down pieces of freeway over them, but emergency deconstruction even for freeways isn't subject to permitting and can happen very quickly.